Lubricating grease



A ril 23,1946.

PERCENT SOAP IN GREASE J. M. SCHANT'Z 2,399,063

LUBRIdATING GREASE Filed March 23, 1944 20 4o 50 eo' 20 4o 60 so 200 20 40 so so 300 LIQUID CONSISTENCY OF GREASE RANGE MILLIMETERS PENETRATION IN 5 SEC. AT 70F.

JACOB M. SCHANTZ INVENTOR.

BY mam ATTO NEY Patented Apr. 23', 1946 UNITED ST ES LUBRICATING GREASE Jacob M. Sohanta, Wilmington, DeLaoaignor to Hercules Powder Company, Wilmington, Del a corporation oi Delaware- Application March 2:, 1944, Serial No. 52am 14 Claims.

This invention relates to improved lubricating greases and methods for their production, and more particularly it relates to improved solid lubricating greases containing a hydrogenated rosin soap as an essential ingredient.

It is known in the art that lubricating greases can be prepared by dispersing a metal soap of rosin or rosin oil in a suitable mineral lubricating oil. Generally, a small amount of water is employed in conjunction therewith, the final product being a water-in-oil type emulsion. It has been dimcult, however, to prepare solid lubricating greases in this manner without employing large amounts of the-metal soap of the rosin or rosin oil. With the employment of large amounts of rosin soap compatibility difliculties are encountered. Either the components are almost entirely incompatible, or they are not sufliciently compatible to yield greases of good uniform texture. Graininess and dark colored greases very frequently result. If the metal soap constituent of the grease amounts to as much as 30% or more, black solids result which are entirely useless in .practical application. A factor not to be ignored is the fact that the use of such large amounts of metal soap increases the cost of the resulting grease measurably.

Now in accordance with this invention it has been found that these difllculties are largely avoided in a lubricating grease comprising a metal soap of a hydrogenated rosin having at least about v 50% of the double bonds contained therein saturated with hydrogen. Such greases are characterized by the marked and unusual gel forming characteristics of. the soaps. These greases prepared-from soaps oi rosin which have been rather highly hydrogenated, have an exceptionally high viscosity which cannot be nearly equalled in greases containing the same amount of metal soaps of rosin known to the prlor'art.- The result is that greases can be prepared in accordance with the processes disclosed herein which contain much less soap than has heretofore been required. v

In preparing-these new greases it has been found that the above defined hydrogenated rosin may be dissolved in mineral oil, the hydrogenated rosin then saponifled by the addition of a desired metal compound with agitation at an elevated temperature, and the remainder of the mineral oil thereafter added. An alternative method involves dissolving a prepared metal salt of the hydrogenated rosin in mineral oil at an elevated temperature and diluting the resulting liquid with additional mineral oil with agitation .to achieve the desired concentration of metal soap of the hydrogenated rosin.

In accordance with this invention it is preferred to employ a small amount or water as an ingredient at some point during the preparation of the grease such that the resulting r ase is a water-in-oii type emulsion. It willbe understood,

however, that theuse of water is not absolutely 5 necessary, although desirable. This will be evident from the examples which follow.

Two different procedures were employed in preparing the lubricating greases in the examples.

The first procedure involved the preparation of j the metal soap, as for example, the calcium soap by saponiilcation in situ. The hydrogenated rosin to be saponifled was dissolved in an equal volume of mineral oil and placed in a mixer cup adapted with a stirring mechanism, the cup being im- 7 mersed in .an 'oil bath- The temperature of the mixture was held at 115 C. and with agitation -the addition 01 a lime-calcium acetate mixture, containing about 5% calcium acetate, was begun togetherwlth a few drops of water initially togo catalyze the reaction. The remaining portion of the lime was slowly added, care being taken to prevent excessivefoaming and loss of sample. After a suflicient amount of the lime-calcium acetate mixture was added to make the theoretical diresinate, the reaction was allowed to continue with agitation at 115C. When the mixture became plastic and shiny in appearance (apx.

/2 hr), heating was discontinued and the remaining portion of the oil slowly added. This 3o final addition of the oil was made slowly at the beginning to minimize the formation of granules and to allow a thorough dispersion. Alter all the oil was added, the grease was removed from V A the cup and allowed to set. In those cases where u water-in-oil-emulsions were prepared, 1.0% of water on the basis of the finished grease was added with vigorous agitation at 100 C. and the mixture allowed to cool.

The second procedure followed in the examples 40 involved the making of greases from prepared soaps. The desired soap was dissolved in twice its weight of mineral oil by stirring and heating to 175 C., or above if necessary, under an atmosphere of C02. The mixture was then diluted with the required amount of mineral oil, thoroughly agitated and allowed to cool. In the cases of those greases which were water-in-oil emulsions, 1.0% of water was added with agitation at 100 C. and allowed to cool. In all the examples, the mineral oil employed was Sunoco (S.A.E.-20). I

A series or greases was made up using prepared soaps made from gum rosin and prepared soaps made from gumrosin which had 69% ofthe double bonds thereof saturated with hydrogen. These greases were all of the water-in-oil type emulsion, 1.0% water having been added during the preparation. The calcium content of the resinate of I gum rosin and the resinate oi 69% to hydrogenated I gum rosin was 5.6' and 5.7%, re-

spectively. The resulting greases were tested for consistency onan A. S. T. M. Universal precision penetrometer, the figures given in the following table being the millimeters penetration in 5.0 seconds at 70 F. using a 10.0 gram cone. Other characteristics of the grease were evaluated. The formulations and evaluations follow in Table I.

Referring to the curves on the accompanying drawing, it will be apparent that whereas a satisfactory grease was preparedon the basis of by weight of the calcium soap of the hydrogenated rosin, three times that much, or an increase of 200%, of the' calcium soap of I gum rosin had to be employed to make a material of sufficient consistency that it could be called a grease, Even this material was black in color and of poor texture.

It has been found that other hydrogenated rosin soaps may be employed in place of those prepared from 69% hydrogenated rosin. Thus, soaps prepared from hydrogenated rosins having at least about 50% of the double bonds thereof saturated with hydrogen may be employed and they have been found to exhibit this unusually strong gel forming characteristic in conjunction with mina'ration of the lead-type grease no-water was emeral oils. Tests have shown that soaps prepared from hydrogenated rosins of less than saturation do not exhibit this property to any marked degree.

Another series of greases was-made up using direct saponification in situ and substituting a hydrogenated wood rosin in place of the hydrogenated gum rosin employed above. 'In this series there were included greases made up using mixtures of tallow fatty acids and hydrogenated gum and wood rosins. In allot the greases in this series theflnished greases contained 14.6%

soap. The greases were aliwater-in-oil type emulsions, 1.0% water being employed. The saponification time was 60 minutes at a tempera-, ture of C. in each case. Where tallow fatty acid was employed as one of the constituents, Emery F-l fatty acid was used. The formulations and evaluations follow in Table II.

Table 11 Properties of grease Acid constituents Consistwe Remarks (607 h dro enated wood rosin)---" 122 Transparent grease. (00%: lrgrdrogenated wood rosin) 200 Bolt, transparent 50% I gum resin (60% hydrogenated), Soft grease.

50% tallow iatty acid. V 60% wood rosin.(00% hydrogenated), 235 Do.

60% tallow fatty acid. i

10% soap used.

Additional greases were made up on the basis of soaps other than calcium soap. In the prepployed, whereas in the preparation of the barium grease 1% water was employed to form a waterin-oil' type emulsion. The lead-type grease was made from a prepared soap containing the theoreticalamount of lead for the diresinate, whereas the barium-type grease was made by direct saponification in oil. The properties of the resuiting greases are given in the following table in conjunction with those of a grease made from a prepared calcium diresinate of a 60% hydrogenated wood rosin, This particular grease contained 1% water and was' a water-in-oil type emulsion. The results followin'Table III.

Table III Propertiesof grease Type grease i ig v Consistency Remarks Lead 15.0 178 Transparent grease. Barium 15.0 225 Do. Calcium 20.0 138 D0.

The hydrogenated resin which is utilized in accordance with this invention may be made according to any of the known methods of hy-' drogenation, as for example, by treatment of the rosin in molten form or in solution in a volatile organic solvent with hydrogen in the presence of a hydrogenation catalyst such as the noble metal catalysts as platinum, rhodium, iridium, ruthenium, palladium, osmium; the base metal catalysts as nickel, nickel-aluminum, nickel-silicon, etc., or the copper chromite type catalysts. The hydrogenation is carried; out to provide a hydrogenated rosin in which at least 50% of the double bonds thereof are saturated with hydrogen. Preferably, a hydrogenated rosin having at least 60% of the double bonds thereof satube wood rosin, gum rosin, or the acids'containedtherein, as abietic, pimaric, sapinic, etc.. acids. Either before or after hydrogenation the rosin may be subjected to vacuum distillation to remove the light end or to remove a particular fraction. If desired, it may be subjected to a refining treatment with a. selective color body solvent or adsorbent, as furfural', phenol, fuller's earth, etc.

when, as indicated by the examples, it is desired to prepare a lubricating grease by employing a prepared resinate, the resinateemployed may be any of those prepared by methods known to the art. .Thus, any of the rosins or modified rosins set forth hereinabove may be hydrogenated by the methods indicated hereinand to the extent required in accordance with this invention, and the resulting hydrogenated rosin or modified rosin saponiiied to form the prepared resinate. Thus. for example, resinatcs may be prepared by melting a sample of hydrogenated rosin at" an elevated temperature, preferably between about c. and about 316 0. The metal is then added to the melt in the form of the acetate. oxide, hydroxide, or other reactive compound,

and the heating is continued until reaction is a carbons, as toluene. etc.. and the aseaoss desired metal compound added thereto.

Alternatively, any or theaforesaid rosins or c ngresses maybe" mmeaunn cmewm less than metal soap of hydrogenatedjrosin on vention that the soaps which have unusually strong gel forming characteristics and which produce particuiarlysatisfactory greases are. the

calcium, barium and lead-soaps; of these. the

calcium soap is the most desirable. It will be understood, however, that other mineral oilsoluble soaps of rosin having at least 50% of the doublebonds thereof saturated with hydrogen may be employed.

Several of the examples have shown the formation of the soaps of hydrogenated rosin in situ. In preparing greases in accordance with this procedure, the metal compound added may be the acetate; the hydroxide, the oxide or otherreactive compound. The negative radical of the compound employed does not have any appreciable effect on the resulting grease. It has been found, however, that the addition of a small amount of water to the mix during the initial reaction will catalyze the reaction; In making greases containing the calcium soap, the use vof a calcium oxide-calcium acetate mixture has'been found very satisfactory. h v

In preparing greases by the method wherein the soap is formed in situ. the amount of metal I saponiiicatioii.

of the finished grease. Howeveathe total amount-of metal soap in the greases will be at least 10%.

It wlilbe understood minim present these improved'g'rea'ses by the method of saponiflcation .in situ the temperature at which thesaponiflca tion is carried out is notparticularly critical.

Any temperature may be employed above that at which the particular metal compoundemplcyed will react with the hydrogenated rosin.

It is important also not to employ a saponiiication temperature so high that decomposition of the constituents results. As indicated in the examples, .thetemperature of 115 0. has-been found very satisfactory where the. metal compound employed-is calcium oxide catalyzed. with a small amount offcalcium acetate. Other optimum' temperatures would be employed .jwhere compounds are employed; for the different metal In the preparation ofv an improved :grease in accordance with this invention wherein the grease is made from a prepared soap, thetemperature at-which the soap-mineral oil mixtureis'heated is not critical; It is required merely that'the temperature he sumciently high to obtain solution of the soap..;.'1 he'use of an inert atmosphere such as 00: during the-dissolution process is not absolutely'necessary, although desirable.

The improved solid grease prepared in accordance with this invention from hydrogenated rosin compound employed to saponify the hydrogenated rosin may vary; It is preferred, however, to'employ an amount falling within the range between the amount necessary to produce the neutral salt of the acid constituents of the hydrogenated rosin and a 100% excess. Y

The examples show that the soap concentrations in the improved lubricating greases must be at least about 10.0% by weight. Thus, referring to Table I and the attached drawing, utilizing a calcium soap concentration of 10.0%, the resulting composition was a light colored very soft grease. If soap concentrations below 10.0% by weight are employed, the product is not a solid grease but a liquid not possessing the desired characteristics of a grease.

The lubricating greases prepared in accordance with the invention may contain water emulsided therein to the extent of not more than about 10% based on the weight of the total composition. Generally, a much smalleramount of water will be employed. This water may be-added to the grease during preparation or at any time thereafter. The addition-should be accompanied by vigorous agitation at a somewhat elevated temperature, as for example, 100' 0.

It will be understood that any mineral lubricating oil may be employed in producing these the particular one employed in the examples, -i e., Sunoco (S. A. E.-), being merely illustrative. Additional lubricating gg'ijassistants such'a'sf graphite, powdered mica, etc.', may be 'added to these greases to theextent-Ejof as much as by weight of the composition,

As is illustrated by the examples-a fatty acid may be employed in conjunction with hydrogen- .ated rosin in the preparation of desirable greases in accordance with this invention. Thus, for exhaving at least about of the double bonds thereof saturated with hydrogen may be variously employed in industry. They are very suitable for -chassis lubricants, compression grease cups, gear boxes, and other applications where high speeds and very high temperatures are notencountered. The concentrations of soap in these greases will vary depending upon the desired consistency and specific application.

Theadvantages of the invention are manifest. The novel greases which are produced in accordance with the herein described processes are char.- acterized by the marked and unusual gel forming characteristicsof the soaps. Satisfactory greases can now be compounded employing'aas little as 10% soap on the basis of the entire composition; whereas heretofore about three-times that quantity of soap has been required to produce a solid grease. This involves a considerable conservation of material. I

The greases resulting from the improvedprocasses of this invention are of much improved color and texture. Furthermore, the greases'are characteris edby stability to oxidation. The compatibility diiiiculties encountered with the heretofore required use of large amounts of rosin soap are solution or a suspension is not known. It is not intended that the application be limited by the ample, tailow fatty acid as Emery F-l-may be terminology employed inthis respect.

employed. whensuch iattyacids are employed where in the a particular rosin Patent is:

pression is intended to'be'equivalent to a rosin having 60% of the double bonds thereof saturated with hydrogen.

What I claim and desire to. protect sisting of calcium, barium, and lead, said soap being present in the amount of'at least about 10.0% by-weight of the finished grease.

3. A lubricating grease comprising the calcium soap of a rosin having at least about 50% of the double bonds thereof saturated with hydrogen, in conjunction with a mineral oil, said soap being present in'the amount of at least about 10.0% by weight of the finished grease.

4:"A lubricating grease comprising the barium soap of a rosin having at least about 50% of the double bonds thereof saturated with hydrogen, in conjunction with a mineral oil, said soap being presentin the amount of at least about 10.0% by weight of the finished grease.

5.'A lubricating grease comprising the lead soap of a rosin having a least about 50% of the double bondsthereof saturated withhydrogen, in conjunction with a mineral oil, said soap being present in the amount of at least about 10.0% by weight of the finished grease.

6. A lubricating grease comprising a mineral oil-soluble soap of a rosin having at least about 60% of the double'bonds thereof saturated with hydrogen, in conJunction with a mineral oil. said soap being present in-the amount of at least about 10.0% by weight of the finished grease.

7. A lubricating grease comprising a-mineral oil-soluble soap of a rosin having at least about 60% of the double bonds thereof saturated with hydrogen, in conjunction with a mineral oil and by Letters asoaooe is described as 60% hydrogenated," etc., the ex- OI um 8. A lubricating grease comprising a'mineral oil-soluble soap of a rosin having at least about 60% of the double 'bondsthereof saturated with hydrogen, in conjunction with a mineral oil and 'no't' more than 10% water on the basis of the finished grease, said soap being present in the amount of at least about 10.0% by weight or the finished grease.

9. A lubricating grease comprising the calcium soap of a rosin having at least, about 60% of the double bonds thereof saturated with hydrogen, in conjunction with a mineral 011, said soap being present inthe amount of at least about 10.0% by weight of the finished grease.

10. A lubricating grease comprising the barium soap of a rosin. having at least about 60% of the double bonds thereof saturated with hydrogen, in comunction with a mineral oil, said soap being present in the amount of at least about 10.0% by'weight of the finished grease.

11. A lubricating grease comprising the ,lead soap of a rosin having at. least about 60% of th double bonds thereof'saturated with hydrogen, in conjunction with a mineral oil, said soap being present in the amount of at least'about 10.0% by weight of the finished grease.

12. A lubricating grease comprising a mineral oil-soluble'soap of a rosin having at least about of the double bonds thereof saturated with hydrogen and a mineral oil-soluble soap of a fatty acid, in conjunction with a mineral oil, said soap of a rosin being present in the amount of at'least about 10.0% by weight of the finished grease.

13. A lubricating grease comprising the calcium soap of a rosin having at leastabout of the double bonds thereof saturated with hydrogen, in conjunction with a mineral oil and a small amount of water, said soap being present in the amount of at least about 10;0% by weight v of the finished grease.

14. A lubricating grease comprising the barium soap of a rosin having at least about 60% of the double bonds thereof saturated with hydrolo-gen, in conjunction with a mineral oil and a small a small amount of water, said soap being present m the amount of at least about 10.0% by weight to of the finished grease.

JACOB M. .SCII-IANTZ. 

